Cargo platforms that are operable as elevators, and that are storable somewhere about the truck's body so as to be movable with the truck, are well known in the prior art. Such cargo platforms may function solely as elevators, or they may also function as complete or partial closures in the form of doors or tailgates for the cargo area of the truck body. Although such cargo platforms which incorporate an elevator function have been used with the rear of trailer truck bodies for many years, an elevator step which can also function as a spill plate for a waste disposal truck has not heretofore been appreciated.
Waste disposal trucks, by design, traditionally have relatively high entrance ports at the rear of the container attachments in order to increase waste storage volume in the hopper. Entrance ports which are too low would allow for spillage of stored waste materials and thus greatly decrease the hopper volume.
Although increased hopper volume is a desirable characteristic, increasing volume by means of a relatively high entrance port at the rear of the truck container attachment is not without drawbacks. For example, trash disposal operators are required to lift extremely heavy objects including metal containers full of disposable materials over the lip at the rear of the container attachment thus emptying the waste materials into the hopper. When a container attachment is designed with a high entrance port, waste disposal which can result in discomfort and injury.
An object of the present invention is to increase hopper capacity while minimizing the above-mentioned drawbacks usually accompanying such design.
A further object of the present invention is to eliminate or greatly reduce refuse spillage from the hopper area.
A still further object of the present invention is to permit the dumping of refuse containers hydraulically in combination with a continuously variable rear step for use by operating personnel.
An additional object of the present invention is to provide a rear step which allows for heavy or bulky items to be raised automatically into position for easier placement into a truck hopper.
Yet another object of the present invention is to combine, in a single mechanism, an hydraulically operated lift platform and spill plate for increasing hopper size without decreasing access to the hopper opening.